Large-scale graphene sheet: articles, compositions, methods and devices incorporating same

Abstract

Provided are methods for growing large-size, uniform graphene layers on planarized substrates using Chemical Vapor Deposition (CVD) at atmospheric pressure; graphene produced according to these methods may have a single layer content exceeding 95%. Field effect transistors fabricated by the inventive process have room temperature hole mobilities that are a factor of 2-5 larger than those measured for samples grown on commercially-available copper foil substrates.

What is claimed: 
     
       1. A method of fabricating graphenic material, comprising:
 growing a sheet of graphene atop an electropolished metallic substrate by contacting the substrate with a hydrocarbon gas at a concentration of less than about 2000 ppm, the contacting being performed such that the resulting graphenic material comprises greater than 95% single layer graphene. 
 
     
     
       2. The method of  claim 1 , wherein the metallic substrate is substantially nonreactive to carbon. 
     
     
       3. The method of  claim 1 , wherein the metallic substrate comprises copper, rhodium, ruthenium, iridium, platinum, cobalt, nickel, or any combination thereof. 
     
     
       4. The method of  claim 3 , wherein the metallic substrate comprises copper. 
     
     
       5. The method of  claim 3 , whereby the room temperature hole mobility of the graphenic material is from about 400 to about 600 cm 2 /V-s. 
     
     
       6. The method of  claim 1 , wherein the graphene sheet has a cross-sectional dimension of at least about 25 cm. 
     
     
       7. The method of  claim 1 , wherein the contacting occurs at from about 50° C. to about 2000° C., about 100° C. to about 1500° C., or about 500° C. to about 1100° C. 
     
     
       8. The method of  claim 1 , wherein the hydrocarbon gas is present at less than about 50 ppm. 
     
     
       9. The method of  claim 1 , wherein the contacting occurs at atmospheric pressure. 
     
     
       10. The method of  claim 1 , further comprising isolating the graphene sheet. 
     
     
       11. The method of  claim 10 , wherein the isolating comprises removing at least a portion of the metallic substrate so as to expose at least a portion of the graphene sheet. 
     
     
       12. The method of  claim 1 , wherein the metallic substrate is disposed atop an insulator or a semiconductor. 
     
     
       13. The method of  claim 12 , wherein the semiconductor comprises silicon. 
     
     
       14. The method of  claim 1 , wherein the roughness of the planarized metallic substrate is reduced by at least a factor of at least 2, or at least 5, relative to a non-planarized metallic substrate. 
     
     
       15. A graphene sheet or layer made according to  claim 1 .